method for controlling a matrix lighting system for an automobile

Abstract

The invention relates to a control method which, following the detection, identification, and localization of a reflective object on a road scene by an optical device, selectively controls light sources (211) of a lighting system (21) in order to modulate their emission of light rays (LR) to attenuate the illumination of the reflective object and limit glare for the driver of a motor vehicle equipped with such a lighting system (21). Advantageously, the light sources (211) thus controlled form part, at least in part, of a first group (214) associated with the generation of a lower portion (FL2) of a light beam (FL) located below a cutoff line (LC). Figure to be published with the abstract: Fig. 2

Description

Title of the invention: Method for controlling a matrix lighting system for a motor vehicle

[0001] The technical context of the present invention is that of automotive lighting systems, in particular matrix lighting systems that allow for non-homogeneous and selective illumination of a road scene. More specifically, the invention relates to a method for controlling such a lighting system.

[0002] In the prior art, lighting systems comprising a plurality of selectively controlled light sources are known, the light sources generating light beams shaped by projection optics according to the light beam. In particular, the light sources of such lighting systems are arranged in a grid, each light source illuminating a given angular segment of a road scene located in front of the motor vehicle. By selectively controlling each of the light sources, it is possible to control the illumination of each angular segment of the road scene.

[0003] As is known, the presence of road signs at the edge of the road scene leads to reflections towards the driver. Depending on the intensity of the light reflected by these road signs, this reflection can cause discomfort to the driver and result in unwanted eye strain.

[0004] Methods for controlling matrix lighting systems are known in order to selectively control the light intensity of a light source in order to generate a complex light beam whose light intensity varies according to the angular segment considered.

[0005] In particular, document EP2085688 is known, which describes a method for controlling such a matrix lighting system to generate a high beam of the type of a high beam, having a vertical distribution of the light sources generating the beam. When an object is present that reflects part of the detected light beam in the upper part of the beam, relative to a cutoff line of a low beam, the light sources associated with illuminating the detected object are switched off to reduce glare for the driver. In this document, it is indeed the upper part of the light beam that is analyzed and controlled to reduce glare.

[0006] We also know of document US9981593 which describes an adaptive lighting system configured to perform different lighting functions, including in particular a low beam type light beam, a high beam type light beam glare-free driving, and an adaptive light pattern function. In this document again, it is the upper part of the light beam, the part associated with the high beam, that is analyzed and controlled in order to reduce glare.

[0007] A technical problem not solved by the prior art lies in the precise control of the lower part of the light beam, that associated with the dipped headlights. Indeed, given the position of road signs, high above the road, they are generally illuminated by the light sources forming the upper part of the light beam. For this reason, and for the sake of economy and simplification of controlled lighting systems, only the light sources associated with the upper part of the light beam have a luminous intensity that is controlled to reduce excessive reflection on such road signs.

[0008] However, in certain driving situations - such as for example in roadwork zones - or according to a road profile - such as for example near a summit, some of the highly retroreflective objects, or even some road signs, are low enough to be totally or partially located below the cut-off line of the dipped beam.

[0009] In such situations, the angle of incidence between an observation direction of the reflecting object and the reflected light beam is smaller than that observed for road signs placed higher and located above the cutoff line. This results in a higher intensity of reflected light and a higher level of discomfort or glare for the driver.

[0010] Furthermore, the resulting illumination at the observer's level (driver or passengers of the vehicle) depends strongly on the distance of the object. The closer the object, the greater the illumination.

[0011] The present invention aims to propose a new control method in order to address at least largely the previous problems and to lead to other advantages.

[0012] Another objective of the invention is to limit the glare of the driver, particularly in the presence of reflective objects located near the road or near a summit.

[0013] Another object of the invention is to reduce driver glare in roadwork areas.

[0014] Another object of the invention is to reduce the glare of the driver when looking at distant, highly reflective objects.

[0015] According to a first aspect of the invention, at least one of the aforementioned objectives is achieved with a method for controlling a lighting system configured to generate a beam of light on a road scene located in front of a motor vehicle, the lighting system comprising a plurality of light sources that can be selectively controlled, the light sources generating light rays shaped by a projection optic according to the light beam, the control process comprising the following steps:

[0016] - a step of detecting at least one object reflecting a part of the beam luminous, the detection stage being implemented by an optical device located at the front of the motor vehicle;

[0017] - a step of determining parameters associated with each at least one object bending, the parameters comprising, for each at least one reflective object, coordinates allowing the location of the reflective object in question in the road scene, and an estimator of a light reflection of said reflective object in question;

[0018] - a step of selecting at least one reflective object for which an illuminance must be reduced, said target object;

[0019] - a step of identifying at least one light source illuminating each at minus a target object, called the target light source;

[0020] - a step of decreasing the light intensity of each at least one source luminous target;

[0021] In the control method according to the first aspect of the invention, at least a part - forming a first subset - of the at least one target light source controlled during the light intensity reduction step is part of those producing a lower part of the light beam located below a cutoff line of a dipped headlight.

[0022] In the context of the present invention, the lower part of the light beam generated by the lighting system forms a light beam of the type of a dipped headlight. To this end, the light sources used to generate such a dipped headlight-type light beam form a first group of light sources of the lighting system.

[0023] In the context of the present invention, the upper part of the light beam generated by the lighting system forms a complementary light beam to the dipped beam, referred to as the upper light beam, together forming a light beam of the type of a main beam. For this purpose, the light sources used to generate such an upper light beam constitute a second group of light sources in the lighting system.

[0024] Thus, to form a light beam of the type of a high beam, the first group and the second group of light sources are used; to form a light beam of the type of a low beam, only the light sources of the first group are used.

[0025] In the context of the present invention, the cutting line extends across the The road scene is defined by a plane extending from the light sources of the lighting system to 10 milliradians below a horizontal plane extending from said lighting system. The cutoff line forms an upper border separating the lower portion of the road scene illuminated by such a low beam from an upper portion of the unlit road scene. In other words, the cutoff line marks a boundary between a light area below the cutoff line and a dark area above the cutoff line.

[0026] In the context of the present invention, the dividing line comprises, for right-hand traffic, a right-hand part, a central part and a left-hand part:

[0027] - the left part of the cutting line extends horizontally on the left side of the motor vehicle, above a horizontal line passing through the axis of the lighting systems forming the front lights of the motor vehicle;

[0028] - the right part of the cutting line extends horizontally on the right side of the motor vehicle, below a horizontal line passing through the axis of the lighting systems forming the front lights of the motor vehicle;

[0029] - the central part of the cutting line extends in an inclined manner, for example at 45°, between the right part and the left part.

[0030] Of course, for right-hand traffic, the left and right parts are respectively reversed.

[0031] The cut-off line is shaped by the projection optics of the lighting system. The projection optics take the form of one or more lenses that shape the light beam in a predefined direction. Optionally, the projection optics also include one or more reflectors to more clearly define the cut-off line.

[0032] In the context of the present invention, the light sources are preferably of the type of one or more light-emitting diodes.

[0033] In the context of the present invention, the lighting system comprises a plurality of light sources. As mentioned previously, the lighting system comprises:

[0034] - a first group of configured light sources, that is to say arranged and oriented, to generate a low beam type light beam. In other words, the first group of light sources is configured to generate a light beam that extends below the cutoff line.

[0035] - a second configured group of light sources, i.e. arranged and oriented, to generate the complementary light beam that extends above the cut line.

[0036] In the context of the present invention, the optical device makes it possible to detect a light signal coming from the front of the motor vehicle in order to be able to to interpret the road scene and, in particular, to be able to distinguish one or more reflective objects on the road scene, or vehicles located on the same traffic lane or on an adjacent traffic lane. By way of non-limiting example, the optical device may take the form of a camera and / or one or more photodiodes.

[0037] In the context of the present invention, the determination step, the selection step, the identification step, and the reduction step are performed by a control unit. The control unit is, for example, a microcontroller or a processor. Generally, the control unit includes computing means and storage means, taking the form, for example, of a memory area.

[0038] Thus, according to the invention, the first identified subset of at least one target light source is at least part of the first group of light sources used to illuminate a lower area of ​​the road scene, in low beam or high beam mode. The first subset may be all or part of the first group of light sources. The first subset does not include any light sources from the second group.

[0039] Thus, the piloting method according to the invention makes it possible to reduce the glare of the driver in a number of situations not managed by the lighting systems known until then, such as in particular the glare caused by the reflection of light on a road sign placed on the ground, such as those found in work zones, or near a road crest.

[0040] The piloting method according to the first aspect of the invention advantageously comprises at least one of the following improvements, the technical characteristics forming these improvements being able to be taken alone or in combination:

[0041] - the step of decreasing the light intensity of at least one light source target includes a current-driving step for said at least one target light source. In other words, an intensity and / or a frequency and / or a phase of the current driving each at least one target light source is decreased in order to reduce the luminous intensity of the corresponding light rays generated by said at least one target light source;

[0042] - alternatively, the step of decreasing the light intensity of at least one The target light source includes a step for controlling the duty cycle of said at least one target light source. In other words, a value of the duty cycle of each at least one target light source is decreased in order to reduce the luminous intensity of the corresponding light rays generated by said at least one target light source. In the context of the invention, the duty cycle This corresponds to a periodic evolution of the light source's state, oscillating between an off and an on state. The duty cycle then represents the proportion of such a period during which the light source is controlled to emit a beam of light. It follows that the higher the duty cycle, the greater the luminous flux produced by the light source. Conversely, the lower the duty cycle, the lower the corresponding luminous flux.

[0043] - the selection step includes a step for comparing the estimator of the light reflection from each at least one identified reflective object on the road scene with a light intensity threshold value, each reflective object with a light reflection estimator greater than the threshold value being selected as the target object. The estimator allows quantification of the amount of light reflected by the reflective object, so that comparisons can then be made. As a non-limiting example, the estimator can be established from a light intensity detected by the optical device located at the front of the motor vehicle;

[0044] - the step of identifying at least one light source includes a step of Selection of all light sources where a portion of the generated light rays reaches the coordinates of each selected target object. As mentioned previously, at least some of the selected light sources form the first subset that illuminates the lower part of the road scene. The selected light sources are those that illuminate at least partially one of the selected target objects. By "partially illuminates," we mean that a significant portion of the light rays emitted by the light source reaches the target object. As a non-limiting example, a light source can be selected as soon as it contributes at least 10% of the illumination to the target object.

[0045] - the coordinates associated with each target object form a box enclosing in the space of the road scene, the target object. Thus, the coordinates include, in particular, (i) an angle delimiting a left edge of the target object, called the left angle, (ii) an angle delimiting a right edge of the target object, called the right angle, (iii) an angle delimiting a lower edge of the target object, called the lower angle, (iv) an angle delimiting an upper edge of the target object, called the upper angle. Thus, all light sources that contribute to the illumination of an angular segment between the left angle, the right angle, the lower angle, and the upper angle are selected;

[0046] - the parameters associated with each target object also include an identifier of the target object, in order to determine in particular whether the target object is of the type of a motor vehicle or a lighted sign;

[0047] - the parameters associated with each target object also include a number defining a distance separating the target object from the motor vehicle on which the lighting system is mounted;

[0048] - the parameters associated with each target object also include a first number reporting a scrolling speed of the target object to the left of the road scene, and a second number reporting a scrolling speed of the target object to the right of the road scene;

[0049] - the step of reducing the light intensity generated by the light source(s) Target miners allow the light reflection from at least one target object to be reduced below a threshold level. The threshold level is a threshold of light intensity - as perceived by the optical device - and which accounts for a state of illumination of the target object that does not dazzle the driver;

[0050] - the identification step includes the identification of target light sources - forming a second subset – configured to produce an upper portion of the light beam located above the cutoff line. As mentioned previously, at least some of the light sources thus selected – those not belonging to the first subset – form the second subset, which illuminates the upper portion of the road scene. Advantageously, the control method according to the first aspect of the invention now allows for the selective control of all the light sources in the lighting system to modulate their light intensity based on reflection from a target object located anywhere on the road scene.

[0051] According to a second aspect of the invention, a lighting assembly for a motor vehicle is proposed, the lighting assembly comprising means configured to implement the control method according to the first aspect of the invention or according to any one of its improvements.

[0052] More specifically, the means include:

[0053] - at least one lighting system comprising a plurality of light sources The light sources, which can be selectively controlled, generate light beams, and the projection optics are configured to shape the light beams to form the light beam projected in front of the motor vehicle.

[0054] - a control unit configured to implement the selection step, the identification step and the reduction step of the piloting process according to the first aspect of the invention.

[0055] In the context of the present invention, each lighting system is preferably a front light of the motor vehicle.

[0056] According to a third aspect of the invention, a motor vehicle is proposed comprising a lighting assembly conforming to the second aspect of the invention.

[0057] Various embodiments of the invention are provided, incorporating, according to all their possible combinations, the different optional features set out here.

[0058] Other features and advantages of the invention will become apparent from the following description on the one hand, and from several illustrative and non-limiting examples of embodiments given with reference to the accompanying schematic drawings on the other hand, in which:

[0059] [Fig-1] illustrates a motor vehicle conforming to the third aspect of the invention;

[0060] [Fig.2] illustrates a schematic view of a lighting system controlled by the process of piloting in accordance with the first aspect of the invention;

[0061] [Fig.3] illustrates a synoptic diagram of the piloting process conforming to the first aspect of the invention;

[0062] [Fig.4] illustrates several situations of use of the piloting method in accordance with first aspect of the invention.

[0063] Of course, the features, variants, and different embodiments of the invention can be combined in various ways, provided they are not incompatible or mutually exclusive. In particular, variants of the invention may be conceived comprising only a selection of features, described hereafter in isolation from the other described features, if this selection of features is sufficient to confer a technical advantage or to differentiate the invention from the prior art.

[0064] In particular, all the variants and all the embodiments described are combinable with each other if nothing prevents this combination from a technical point of view.

[0065] In the figures, the elements common to several figures retain the same reference.

[0066] With reference to [Fig. 1], a motor vehicle 1 is illustrated, comprising a detection assembly according to the invention in its second aspect. Such a detection assembly comprises:

[0067] - at least one lighting system 21 for forming the light beam FL projected in front of the motor vehicle 1;

[0068] - an optical device 22 configured to detect a light signal from the scene of any location in front of the motor vehicle 1 in order to be able to identify in particular one or more reflective objects OBJ on the road scene SR. By way of non-limiting example, the optical device 22 may take the form of a camera and / or one or more photodiodes;

[0069] - a control unit configured to implement selection step 33, the identification step and the reduction step 34 of the piloting process 3 conforms to the first aspect of the invention.

[0070] As seen in [Fig.1], each lighting system 21 is preferably a front light of the motor vehicle 1. In addition, the optical device 22 is preferably of the type of a camera and / or one or more photodiodes located at the front face of the motor vehicle 1.

[0071] With reference to [Fig.2], the lighting system 21 comprises a plurality of light sources 211 each generating light rays RL which are shaped by a projection optic 212 in order to form the light beam FL.

[0072] The light sources 211 are preferably of the type of one or more light-emitting diodes. They are arranged in a one-dimensional or two-dimensional array comprising:

[0073] - a first group 214 of configured light sources 211, that is to say arranged and oriented to generate a low beam type FL light beam. In other words, the first group 214 of the light sources 211 is configured to generate a lower part FL2 of the FL light beam which extends below the cutoff line LC.

[0074] - a second group 213 of configured light sources 211, that is to say arranged and oriented, to generate an upper part FL1 of a high beam type FL light beam, forming a complementary FL light beam which extends above the LC cutoff line.

[0075] With reference to [Fig.3], the invention relates to a method for controlling 3 such a lighting system 21, the control method 3 comprising the following steps:

[0076] - a detection step 31 of at least one object OBJ reflecting a part of the light beam FL, the detection step 31 being implemented by an optical device 22 located at the front of the motor vehicle 1;

[0077] - a step of determining 32 parameters associated with each at least one object reflective OBJ, the parameters including, for each at least one reflective OBJ object, coordinates allowing the reflective OBJ object considered to be located in the SR road scene, and an estimator of a light reflection of said reflective OBJ object considered;

[0078] - a selection step 33 of at least one reflective object OBJ for which a illumination must be reduced, says target object OBJ;

[0079] - a step of identifying at least one light source 211 illuminating each at minus one target object OBJ, called target light source 211;

[0080] - a step of decreasing 34 of a luminous intensity of each at least one target light source 211, at least a part - forming a first subset - of the at least one target light source 211 driven during the reduction step 34, being part of that(s) generating the light rays RL of the lower part FL2 of the FL light beam located below the LC cutoff line.

[0081] The step 34 for reducing the luminous intensity of at least one target light source 211 includes a step for controlling the current of said at least one target light source 211, so as to decrease an intensity and / or a frequency and / or a phase of the current driving each at least one target light source 211. Alternatively, the step 34 for reducing the luminous intensity of at least one target light source 211 includes a step for controlling the duty cycle of said at least one target light source 211 in order to reduce the duration – for a given cycle – during which the light source emits its light rays RL.

[0082] The step of identifying at least one target light source 211 includes a step of selecting all the light sources 211 of which a part of the generated light rays RL reaches at least one of the at least one target object OBJ.

[0083] Thus, the control method 3 described here allows the selection, among the light sources 211 of the first group 214, of those that contribute to excessively illuminating the identified target object OBJ. Consequently, the control method 3 controls the light sources 211 thus identified in order to reduce the luminous flux produced by them, thereby reducing the luminous flux reaching the identified target object OBJ, reducing its illumination and, consequently, the intensity of the reflection produced by it.

[0084] This advantageous configuration thus makes it possible to resolve glare situations not previously addressed, which are illustrated in [Fig.4]:

[0085] - the first diagram - the one at the top - illustrates a nominal lighting situation of a road scene SR, the light beam FL generated and shaped by the lighting system illuminating said road scene SR in front of the motor vehicle 1;

[0086] - the second diagram - the middle one - illustrates a lighting situation of a road scene SR on which a reflective object OBJ is present at ground level. This could be, for example, a road sign indicating the temporary presence of roadworks. On a road panel, as shown here, the target object OBJ is not illuminated by the upper part FL1 of the light beam FL. Conversely, the target object OBJ is illuminated by the lower part FL2 of the light beam FL. The control method 3 according to the invention is then able to detect this reflective object OBJ located very low on the road scene SR, and to act on the light sources 211 of the first group 214 in order to reduce their generated luminous flux to attenuate the illumination of the target object OBJ and - in fact - reduce the glare for the driver;

[0087] - the third diagram - the bottom one - illustrates a lighting situation of a SR road scene in which motor vehicle 1 is located uphill on a descending road, the vehicle having not yet begun the descent. If an OBJ object is defined as- If a reflective object is present along the road, such as a traditional road sign, then the latter is illuminated by the lower part FL2 of the light beam FL, and not by its upper part FL1. The control method 3 according to the invention is then able to detect this reflective object OBJ located below the motor vehicle 1, and to act on the light sources 211 of the first group 214 in order to reduce their generated luminous flux to attenuate the illumination of the target object OBJ and - in fact - reduce the glare for the driver.

[0088] According to another aspect of the invention, the control method 3 according to the invention extends its functionalities to possible light sources 211 of the second group 213 in order to be able to attenuate their luminous flux if they contribute, in addition to light sources 211 of the first group 214, to illuminating a target object OBJ identified previously.

[0089] In summary, the invention relates to a control method 3 which, following the detection, identification and localization of a reflective object OBJ on a road scene SR by an optical device 22, selectively controls light sources 211 of a lighting system 21 in order to modulate the emission of light rays RL to attenuate the illumination of the reflective object OBJ and limit glare for the driver of a motor vehicle 1 equipped with such a lighting system 21. Advantageously, the light sources 211 thus controlled are part, at least in part, of a first group 214 associated with the generation of a lower part FL2 of a light beam FL located below a cutoff line LC.

[0090] Of course, the invention is not limited to the examples just described, and many modifications can be made to these examples without departing from the scope of the invention. In particular, the various features, forms, variants, and embodiments of the invention can be combined with one another in various ways, provided they are not incompatible or mutually exclusive. Specifically, all the variants and embodiments described above are combinable.

Claims

Demands

1. A method of controlling (3) a lighting system (21) configured to generate a light beam (FL) on a road scene (SR) located in front of a motor vehicle (1), the lighting system (21) comprising a plurality of light sources (211) that can be selectively controlled, the light sources (211) generating light rays (RL) shaped by a projection optic (212) according to the light beam (FL), the method of controlling (3) comprising the following steps: - a detection step (31) of at least one object (OBJ) reflecting a part of the light beam (FL), the detection step (31) being implemented by an optical device (22) located in front of the motor vehicle (1);- a step of determining parameters associated with each at least one reflective object (OBJ), the parameters comprising, for each at least one reflective object (OBJ), coordinates allowing the location of the considered reflective object (OBJ) in the road scene (SR), and an estimator of a light reflection of said considered reflective object (OBJ); - a step of selecting (33) at least one reflective object (OBJ) for which an illuminance must be reduced, called the target object (OBJ); - a step of identifying at least one light source (211) illuminating each at least one target object (OBJ), called the target light source (211); - a step of reducing the light intensity of each at least one target light source (211);characterized in that at least a part - forming a first subset - of the at least one controlled target light source (211) during the step of decreasing the light intensity (34) is part of those producing a lower part (FL2) of the light beam (FL) located below a cutoff line (LC) of a dipped beam.;

2. A control method (3) according to claim 1, wherein the step of reducing the light intensity of at least one target light source (211) comprises a current control step of said at least one target light source (211).

3. A control method (3) according to claim 1, wherein the step of reducing the light intensity of at least one source luminous target (211) includes a step of driving a duty cycle of said at least one luminous target (211).

4. A piloting method (3) according to any one of the preceding claims, wherein the selection step (33) comprises a step of comparing the light reflection estimator of each at least one reflective object (OBJ) identified on the road scene (SR) with a threshold value of light intensity, each reflective object (OBJ) having a light reflection estimator greater than the threshold value being selected as the target object (OBJ).

5. A control method (3) according to any one of the preceding claims, wherein the step of identifying at least one light source (211) includes a step of selecting (33) all the light sources (211) of which a portion of the generated light rays (RL) reaches the coordinates of each selected target object (OBJ).

6. A control method (3) according to any one of the preceding claims, wherein the step of reducing the light intensity generated by the at least one target light source (211) makes it possible to reduce the light reflection of the at least one target object (OBJ) in order to make it below a threshold level.

7. A piloting method (3) according to any one of the preceding claims, wherein the identification step comprises an identification of target light sources (211) - forming a second subset - configured to produce an upper part (FL1) of the light beam (FL) located above the cutoff line (LC).

8. Lighting assembly (2) for motor vehicle (1), the lighting assembly (2) comprising means configured to implement the control method (3) according to any one of the preceding claims.

9. A light assembly (2) according to the preceding claim, wherein the means comprise: - at least one lighting system (21) comprising a plurality of light sources (211) that can be selectively controlled, the light sources (211) generating light beams (RL), a projection optic (212) configured to shape the light beams (RL) to form the light beam (FL) projected in front of the motor vehicle (1); - a control unit configured to implement the selection step (33), the identification step and the reduction step (34).

10. Motor vehicle (1) comprising a lighting assembly (2) according to any one of claims 8 or 9.

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